text: /**
   * Simple cart Item model with these properties
   * @property sku
   * @property quantity
   * @property discount
   */
  module.exports = class CartItem {
    constructor(sku) {
      // check is sku is empty/undefined/null or not a string
      if (!sku || typeof sku !== "string") {
        throw new Error("Invalid sku");
      }
  
      this.sku = sku;
      this.quantity = 1;
      this.discount = 0;
    }
  };
  